Microarrays have revolutionized biology over the past ten years. As a result, instrumentation for manufacturing and reading spotted microarrays has been widely commercialized. The initial technology for spotting cDNA has now been extended to include spotting other materials, including small molecules, oligonucleotides, proteins (e.g., enzymes, antibodies, etc.), whole cells, and tissue specimens. To a large degree, the technology has now settled on a standard format; microarrays are manufactured on 25 mm by 75 mm glass slides that are 1 mm thick.
At the same time, high throughput robotics has been developed for biomedical and pharmaceutical research. In this area, instruments are designed to handle microtiter plates. These plates are approximately 85 mm by 125 mm. Wells in these plates are designed with standard spacing. A 96-well plate has twelve columns and eight rows with 9 mm spacing between the centers of adjacent wells. A 384-well plate has twenty-four columns and sixteen rows with 4.5 mm spacing between the centers of adjacent wells. A 1536-well plate has forty-eight columns and thirty-two rows with 2.25 mm spacing between the centers of adjacent wells. Pipetting and plate-washing robots are designed to handle plates of this format.
Traditionally, microarrays are processed by washing them with a single sample at a time, e.g., serum taken from a single patient. With the further extension of microarraying technology, it would be desirable to study the interaction of many different samples with a given microarray of materials. For example, one may want to screen thousands of different serum samples from patients with a microarray of 100 different antibodies. Or, one may wish to screen thousands of different small organic compounds for their ability to disrupt protein-protein interactions in a microarray of 100 different pairs of proteins. To do this, it would be valuable to use the current instrumentation for preparing and scanning microarrays in combination with the current instrumentation for processing samples in microtiter plates.